This invention relates generally to the field of integrated circuits and more specifically to correcting a mask pattern using multiple correction grids.
Masks such as photomasks are typically used in photolithographic systems to define patterns on objects such as integrated circuits. The shape of the mask, however, may sometimes differ from the pattern defined on the object. For example, optical diffraction may cause a resulting pattern defined on an integrated circuit to differ from the shape of the mask. Consequently, masks are typically adjusted to account for these deviations.
In accordance with the present invention, a method and system for correcting a mask pattern are provided that substantially reduce or eliminate disadvantages and problems associated with previously developed systems and methods.
According to one embodiment of the present invention, correcting a mask pattern includes accessing a record associated with an uncorrected pattern that comprises segments. The record associates each segment with a correction grid of a number of correction grids, where each correction grid comprises points. A segment is selected, and an optimal correction for the segment is determined. A correction grid associated with the segment is determined. The segment is snapped to a subset of points of the associated correction grid, where the subset of points is proximate to the optimal correction, to form a corrected pattern of a mask pattern.
Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may be that multiple correction grids are used to correct a mask pattern. A fine grid is used to correct segments that require more precise correction, while a coarse grid is used to correct segments that require less precise correction. The multiple grids may allow for increasing efficiency of the mask correction while maintaining required correction precision.
Certain embodiments of the invention may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.